Abstract: :
Purpose: We have previously shown that proliferation of HumanTenon’s fibroblasts (HTCFs) from diabetic patients isreduced. The aim of this study was to determine the effect hyperglycaemiaon the previously noted changes in proliferation of HTCFs fromdiabetic and non-diabetic patients. We also determined the expressionof cell surface receptors required for control of cellular proliferationin the diabetic and control patients.Methods: Tenon’scapsule fibroblasts from 7 diabetic and 7 non-diabetic patientswere exposed to normo- (5mmol/L) and hyperglycaemic (25mmol/L)conditions and their proliferation determined by 3H thymidineincorporation. The possession of cell surface receptors (PDGFand TGF RII) and intracellular signalling molecules (TGF-ß1,ERK1/2 and MAPK) was determined on lysed and non-lysed cellsby direct immunoblotting.Results: Human Tenon’s capsulefibroblasts (HTCF) derived from diabetic patients exposed toa glucose concentration of 5mmol/L exhibited a significantlyreduced rate of proliferation compared with non-diabetic controlsamples (p=< 0.00001). HTCFs derived from diabetic patientsand cultured in a high concentration of glucose (25mmol/L) for24 hours did not show any significant difference in proliferationcompared with paired samples incubated with 5mmol/L of glucose(Student’s paired t test, p=0.95). However, human Tenon’scapsule fibroblasts derived from age matched control patientscultured in a high concentration of glucose (25mmol/L) showeda significant inhibition in proliferation after 24 hours whencompared with paired samples incubated with 5mmol/L of glucose(student’s paired t test, p=0.0008). All diabetic andnon-diabetic samples were positive for PDGF receptor and intracellularERK1/2 and MAPK, however diabetic cells showed reduced expressionof TGF-ß1.Conclusions HTCFs from diabetic patientsshow reduced proliferation at normo-glycaemic glucose concentrationswhen compared to non-diabetics. High glucose concentrationssuppressed the proliferation of non-diabetic HTCFs. This reductionin proliferation was associated with reduced levels of TGF-ß1expression.